1. Field
Aspects of the present invention relate to an organic light emitting diode (hereinafter referred to as “OLED”) display. More particularly, aspects of the present invention relate to a method of manufacturing an upper electrode electrically connected to an upper electrode power source line and an OLED display including the upper electrode.
2. Description of the Related Art
An OLED display includes a pixel area including a plurality of pixels. Each of the pixels includes red, green, and blue sub-pixels. An organic light emitting element is formed in each sub-pixel and includes a lower electrode, an organic emission layer, and an upper electrode. The organic emission layer is multilayered, and includes a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer.
Upper and lower power source voltage lines are provided outside of the pixel area. The upper and lower power source voltage lines supply the pixel area with a power source voltage. A scan driver is provided outside of the pixel area and outputs a selection signal to the pixel area. A data driver is provided outside of the pixel area and outputs a data signal to the pixel area. An upper electrode power source line is provided outside of the pixel area and supplies the upper electrode with a driving voltage.
The upper electrode power source line is covered with an insulation layer. At least one contact hole is formed in the insulation layer to expose a part of the upper electrode power source line. Further, the upper electrode is formed in the entire pixel area and at the outside of the pixel area (i.e., at least one contact hole). The upper electrode is brought into contact with the upper electrode power source line and is electrically connected thereto.
In a process of forming the organic light emitting element, at least one organic material layer (e.g., the hole injection layer and the hole transport layer) is formed using a liquid coating method, such as spin coating. However, the organic material layer formed using the liquid coating method is formed not only in the pixel area, but also at unwanted areas, including areas for the scan driver, the data driver, and the contact holes for the upper electrode power source line that are formed outside of the pixel area. If the organic material layer formed at the outside of the pixel area is not removed, subsequent processes cannot be smoothly performed. For example, the organic material layer is also formed over the upper electrode power source line exposed by the contact holes. Accordingly, if the organic material layer is not removed, the upper electrode and the upper electrode power source line cannot be connected to each other in a subsequent process of forming the upper electrode.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.